Identifi cation and expression profi le of GbAGL2, a C-class gene from Gossypium barbadense.

ABSTRACT

An AGAMOUS (AG)-like gene, GbAGL2, was isolated from Gossypium barbadense and characterized. Alignment and phylogenetic analysis indicated that GbAGL2 shared high homology with AG-subfamily genes and belonged to a C-class gene family. DNA gel blot analysis showed that GbAGL2 belonged to a low-copy gene family. Reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative real-time PCR (qPCR) revealed that GbAGL2 was highly expressed in reproductive tissues including ovules and carpels, but barely expressed in vegetative tissues. In addition, GbAGL2 expression in a cotton cultivar XuZhou142 (wt) (XZ142, G. hirsutum L.) and its fi breless mutant XZ142 (fl ) was examined. RNA in situ hybridization analysis indicated that GbAGL2 transcripts were preferentially restricted to outer ovule integuments, carpels and fi bres. These expression patterns implied that GbAGL2 might participate in the development of the carpel and ovule. Furthermore, Arabidopsis transformation was performed and modifi cations occurred in fl owers, and the silique length of transgenic plants also increased slightly, suggesting that the GbAGL2 gene may have a positive effect on the development of the ovary or ovule. Our fi ndings suggest that GbAGL2 might not only specify the identity of fl oral organs but also play a potential key role in ovary or fi bre development in cotton.